A device of this type is suitable in particular for use in a plant for the production of so-called multi-packs, in other words, packs each containing a number of individually packed articles, so that such a plant comprises a single-pack machine for the production of packed single articles, a transfer device which is also a group former of the type mentioned in the preamble, and a multi-pack machine for the production of multi-packs. The single-pack machine produces a continuous stream of packed articles which are transferred by the transfer device to the multi-pack machine, so that the speeds of these machines and those of the transfer machine have to be synchronized. The stream of packed articles produced by the single-pack machine is, however, not always constant, since this machine has a facility for blowing rejected packs out of the stream of packed articles and the production speed of this machine depends on the supply thereto of single articles to be packed. The speeds of the transfer device and of the multi-pack machine will therefore have to be capable of varying. However, sudden changes in speed from a specific speed to zero speed and vice versa are not possible in this case. The transfer device therefore also serves as a buffer in which articles can be buffered when the stream of articles coming out of the single-pack machine suddenly begins or decreases with gradually increasing speed of the multi-pack machine, and from which articles can be drawn for supplying the multi-pack machine at gradually decreasing speed whenever a gap occurs in the article supply stream, until this gap is filled up again by the single-pack machine which continues to supply packed articles at full speed.
In the known transfer device the above-mentioned run of the endless chain is guided in such a zigzag manner that between every two drivers a sag is present in the chain, said sags meaning an additional length of this run. In this case the endless chain is driven at one side by the producing machine and at the other side by the processing machine, said drives being synchronized by means of regulating devices. If a gap now occurs in the stream of articles supplied by the producing machine, then the drive of the endless chain is stopped by the producing machine, so that the sags are pulled approximately straight over a period of time by the other drive of the endless chain, with the result that the processing machine remains supplied, during which time the gap is filled up by the producing machine.
The disadvantage of this known device is that it cannot operate at relatively high speeds, since the masses of the chain and moving parts are too great for this. Moreover, in order to obtain great enough extra length of the endless chain, a relatively large number of sags must be present, as a result of which the straight length of the zigzag-shaped run of the endless chain becomes unacceptably great.
The object of the invention is to provide an improved device of the above-mentioned type.